Lab 6: Ultrasonic Waves

Lab 6 of 40B
Ultrasonic Waves

1. Diffraction

Widest Slit - Amplitude versus Angle

Widest Slit - Wave length and Velocity of sound

Diffraction	The Width of the widest slit, A_wide, UNIT: ( )	First Minima, q_{mini 1}, UNIT: (degree)	Wave Length, l = A_wide\|sin q_{mini 1}\|, unit: ( )	Sound Velocity, v = f l , unit:( )
Single Wide Slit

Question 1:

(0.5) Use l = A_widesinq to calculate l.

(0.5) Use your value of l and the ultrasound frequency to compute the speed of sound in air , v = fl

Narrow Slit - Amplitude versus Angle

Widest Slit - Wave length and Velocity of sound

Diffraction	The Width of the narrow slit, A_narrow, UNIT: ( )	First Minima, q_{mini 1}, UNIT: (degree)	Wave Length, l = A_narrow\|sin q_{mini 1}\|, unit: ( )	Sound Velocity, v = f l , unit:( )
Single Narrow Slit

Question 2:

(0.5) Is your wave length l greater than the width of the narrow slit, A_narrow?

(0.5) Read page 36 carefully, write down the reason we do not have a clear pattern for the single-narrow-slit diffraction.

2, Interference

TWO Narrow Slits - Amplitude versus Angle

Widest Slit - Wave length and Velocity of sound

Interference	The Distance between the two narrow slits, d, UNIT: ( )	First Minima, q_{mini 1}, UNIT: (degree)	Wave Length, l = 2 d \|sin q_{mini 1}\|, unit: ( )	Sound Velocity, v = f l , unit:( )
Two Narrow Slits

Question 3:

Additional Question: Please write down a simple conclusion of the whole Lab 6.

Requirement:

(0.5) Write it in no more than 4 sentences.

(0.5) Use some of your data tables, graphs and answered questions to make some quantitative argument.